22 



GEOLOGY OF NIAGARA GORGE. 



At its head at Buffalo the Niagara river flows through 

 a shallow passage in the Onondaga limestone of Devonian 

 age. Thence northward to the falls and down the gorge 

 to the head of Foster's flats all the visible exposures of 

 strata belong to the Silurian system. Below this the only 

 rock exposed is the Queenston shale of Ordovician age, 

 and where not composed of glacial drift, the iiver banks 

 from Queenston to Lake Ontario are composed of this shale. 

 In a paper read before the Geological Society of America 

 at New Haven, Conn., in December 1912, Prof. Chas. 

 Schuchert of Yale University gave an account of recent 

 investigations by himself, Dr. W. A. Parks of Toronto 

 University and Dr. M. Y. Williams of the Canadian Geo- 

 logical Survey, in consequence of which a revision of the 

 Silurian of the Niagara region is suggested. Prof. Schuchert 

 has contributed the following brief statement of the Niagara 

 gorge section : 



Niagara Gorge Section. 



Along line of New York Central railway and Grand 

 Gorge trolley line (see Grabau, Bull. 45, N.Y. State Mu- 

 seum, 1901). 

 Silurian. 



Lockport dolomite. — Thickness as exposed 130 feet 

 (39.6 m.). 



Rochester shale. — Thickness 68 feet (20.7 m.). 

 Clinton upper limestone with an occasional bryozoan 

 reef at top (Irondequoit of Rochester, N.Y.). About 

 10 feet (3.05 m.) thick. 



Crystalline, heavy bedded, highly fossiliferous, 

 pinkish limestone. Fossils essentially those of 

 the Rochester shale. Has zones of stylolites. 

 Clinton lower limestones — (Wolcott or Pentamerus lime- 

 limestone at Rochester, N.Y.) About 15 feet 

 (4.6 m.) thick. 



Thinner bedded magnesian limestones with Ano- 

 plotheca plicatula, Hyatlella congesta, etc. 

 Clinton shale. — About 5 feet (1.5 m.) thick. 



Green to grayish shales with Anoplotheca hemis- 

 pherica and A. plicatula. 

 Probable disconformily. 



